diff options
| -rw-r--r-- | tvix/castore/src/blobservice/mod.rs | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/tvix/castore/src/blobservice/mod.rs b/tvix/castore/src/blobservice/mod.rs index 348f87fb962e..fa6b87926ba1 100644 --- a/tvix/castore/src/blobservice/mod.rs +++ b/tvix/castore/src/blobservice/mod.rs @@ -24,19 +24,22 @@ pub use self::sled::SledBlobService; /// The base trait all BlobService services need to implement. /// It provides functions to check whether a given blob exists, -/// a way to get a [io::Read] to a blob, and a method to initiate writing a new -/// Blob, which will return something implmenting io::Write, and providing a -/// close funtion, to finalize a blob and get its digest. +/// a way to read (and seek) a blob, and a method to create a blobwriter handle, +/// which will implement a writer interface, and also provides a close funtion, +/// to finalize a blob and get its digest. #[async_trait] pub trait BlobService: Send + Sync { /// Check if the service has the blob, by its content hash. + /// On implementations returning chunks, this must also work for chunks. async fn has(&self, digest: &B3Digest) -> io::Result<bool>; /// Request a blob from the store, by its content hash. + /// On implementations returning chunks, this must also work for chunks. async fn open_read(&self, digest: &B3Digest) -> io::Result<Option<Box<dyn BlobReader>>>; /// Insert a new blob into the store. Returns a [BlobWriter], which - /// implements [io::Write] and a [BlobWriter::close]. + /// implements [tokio::io::AsyncWrite] and a [BlobWriter::close] to finalize + /// the blob and get its digest. async fn open_write(&self) -> Box<dyn BlobWriter>; /// Return a list of chunks for a given blob. @@ -44,20 +47,21 @@ pub trait BlobService: Send + Sync { /// The former return value is sent in case the blob is not present at all, /// while the second one is sent in case there's no more granular chunks (or /// the backend does not support chunking). - /// A default implementation signalling the backend does not support - /// chunking is provided. + /// A default implementation checking for existence and then returning it + /// does not have more granular chunks available is provided. async fn chunks(&self, digest: &B3Digest) -> io::Result<Option<Vec<ChunkMeta>>> { if !self.has(digest).await? { return Ok(None); } else { - // default implementation, signalling the backend does not support chunking. + // default implementation, signalling the backend does not have more + // granular chunks available. return Ok(Some(vec![])); } } } -/// A [tokio::io::AsyncWrite] that you need to close() afterwards, and get back -/// the digest of the written blob. +/// A [tokio::io::AsyncWrite] that the user needs to close() afterwards for persist. +/// On success, it returns the digest of the written blob. #[async_trait] pub trait BlobWriter: tokio::io::AsyncWrite + Send + Sync + Unpin + 'static { /// Signal there's no more data to be written, and return the digest of the @@ -67,7 +71,7 @@ pub trait BlobWriter: tokio::io::AsyncWrite + Send + Sync + Unpin + 'static { async fn close(&mut self) -> io::Result<B3Digest>; } -/// A [tokio::io::AsyncRead] that also allows seeking. +/// BlobReader is a [tokio::io::AsyncRead] that also allows seeking. pub trait BlobReader: tokio::io::AsyncRead + tokio::io::AsyncSeek + Send + Unpin + 'static {} /// A [`io::Cursor<Vec<u8>>`] can be used as a BlobReader. |